For the beverage, gas shall be mixed into the liquid beverage usually. For example, much carbon dioxide shall be dissolved into the beverage when a carbonated beverage is prepared, and water and carbon dioxide are generally pressed into the gas-liquid mixing device of the beverage by a pressurization device such as a pump to achieve dissolution of carbon dioxide in water in the gas-liquid mixing device of the beverage. The defects in the prior art lie in that the liquid is mixed with another material directly according to a high-pressure method, and high pressure is required to be kept all the time during the whole process, so that not only the requirement on pressurization equipment, but also the requirement on high-pressure resistance of the whole gas-liquid mixing device is higher; moreover, the energy consumption of high-pressure equipment is much higher than that of low-pressure equipment.